Semiconductor dice must be tested during the manufacturing process to evaluate various electrical parameters of the integrated circuits formed on the dice. Accordingly, different testing procedures have been developed by semiconductor manufacturers for testing semiconductor dice. Standard tests for gross functionality are typically performed by probe testing the dice at the wafer level using probe cards and wafer steppers. Burn-in testing is typically performed after the dice have been singulated and packaged using a burn-in oven or similar testing apparatus in electrical communication with test circuitry. Among the tests performed are dynamic burn-in, input/output leakage, speed verification, opens, shorts, refresh and a range of algorithms to verify AC parameters.
In the case of unpackaged dice, marketed by manufacturers as known good dice (KGD), temporary packages are required to house a single bare die for burn-in and other test procedures. This type of temporary package is described in U.S. Pat. Nos. 5,541,525, 5,519,332 and 5,495,179 to Wood et al.
These temporary packages typically include an interconnect component for establishing temporary electrical communication with the die. The interconnect can include a substrate with contact members for electrically contacting the bond pads or other contact locations on the die. The interconnect can also include conductors, such as metallized traces, for providing a conductive path from testing circuitry to the contact members. Interconnects for temporary packages are disclosed in U.S. Pat. Nos. 5,483,741 and 5,523,697 to Farnworth et al., incorporated herein by reference.
With advances in the architecture of semiconductor devices, it is advantageous to perform some testing of integrated circuits using very high speed testing signals. For example, testing frequencies of 500 MHz and greater are anticipated for some memory products such as DRAMS. The temporary packages and interconnects used to test dice must be capable of transmitting signals at these high speeds without generating parasitic inductance and cross coupling (i.e., "cross talk").
Parasitic inductance and cross coupling can arise in various electrical components of the temporary packages and in the electrical interface of the interconnect with the temporary package. This can adversely effect the test procedure by causing the power supply voltage to drop or modulate during the test procedure and by causing noise and spurious signals.
For example, the conductors on the interconnect are typically wire bonded to corresponding conductive traces and terminal contacts formed on the temporary package. Capacitive coupling can occur between adjacent conductors on the interconnect and between adjacent bond wires to the conductors. High speed switching of the voltage levels in the conductors and bond wires can result in corresponding inadvertent changes in the voltage levels on nearby conductors, or bond wires, resulting in logic errors.
The problems of parasitic inductance and cross coupling can be compounded by the large number of bond pads contained on later generations of semiconductor dice. A large number of bond pads requires a corresponding large number of contact members and conductors on the interconnect. Because of their high density, it can be difficult to locate and construct the contact members and conductors without forming parasitic inductors and initiating cross talk and interconductor noise.
Because of these and other problems, there is a need in the art for improved temporary packages and interconnects for testing semiconductor dice and improved high speed testing methods.